A calendar for the browser that doesn't require any plugins. You can make multiple calendars with

var calendar =newCalendar("calendar id");

and show the calendar with

calendar.showCalendar(input, minDate)

You can pass an input to showCalendar and it will use that input as the default date, change the input when a date is selected and appear next to the input. The calendar also takes in a minimum date that you cannot select less than. Both arguments are optional.